Intelligence and Miscellaneous Articles. 405 



3. By making the flame revolve rapidly in a circle within the 

 tube, it assumes ichen silent the form, as might be expected, of a hol- 

 low cylinder with an even top, lilve the flame of an Argand burner ; 

 but the moment it begins to sing, this luminous cylinder becomes 

 beautifully serrated above, and resolves itself into a series of vertical 

 columns of flame with narrow dark intervals between, thus marking 

 in a very striking way the intermitting nature of the explosive com- 

 bustion, upon which the sound depends. With a tube 6 feet long 

 and \\ inch in diameter, a flame of coal-gas f of an inch long gives 

 an effect which may be distinctly seen over a large room. 



4. I find the simplest arrangement for showing the intermittence 

 of the singing flame at a distance, is a blackened ivlieel having on it a 

 white har in a radial direction, which, when revolving near the sono- 

 rous flame, exhibits a series of white bars arranged symmetrically 

 around the centre. 



Boston, U.S. Yours truly, 

 March 16, 1858. W. B. Rogers. 



NOTE ON THE MODE IN WHICH THE PHOSPHATES PASS INTO 



PLANTS. BY M. P. THENARD. 

 Phosphate of lime is soluble in aerated water, but the phosphates 

 of iron and alumina are insoluble in that fluid. When 50 grammes 

 of one of the soils examined by the author (soils produced by the 

 decomposition of Jurassic rocks) are placed in a Seltzer water-bottle 

 and filled up with aerated water saturated with phosphate of lime, 

 corked and shaken, if the water be filtered in three or four days, the 

 lime is found under the form of carbonate, but not the smallest trace 

 of phosphate. With artificially prepared alumina or oxide of iron in 

 place of the natural soil, the result is identical. In all the soils ex- 

 amined by the author, the phosphates always had a sesquioxide 

 (alumina or iron) for their base, and never a protoxide (lime or 

 magnesia). And when phosphate of lime was mixed with the soils, 

 the action of the rains and a few weeks of contact were sufficient to 

 cause the complete disappearance of the phosphate added. 



In the list of natural elements to which agricultural chemists have 

 directed their attention, there is not one which dissolves the sesqui- 

 phosphates ; so that we might logically conclude that, as the sesqui- 

 oxides are only contained in plants in infinitesimal quantities, the 

 plants ought to be almost completely destitute of phosphoric acid. 

 There must consequently be some special arrangement for the intro- 

 duction into plants of the considerable amount of phosphoric acid 

 found in their ashes. 



In studying the silicates, the author was led to think that certain 

 silicates of lime must be far more soluble than was generally sup- 

 posed ; on treating a great excess of chloride of calcium dissolved in 

 a large quantity of water, with a silicate of soda as neutral as pos- 

 sible, the silicate of lime formed had the power of dissolving freely 

 in water in the proportion of 6 decigrms. per litre. 



Reflecting on the insolubility of the silicates of alumina and iron 

 and of phosphate of lime in water, and tlie solubility of the latter in 

 aerated water, the author was led to suspect that it might be by 



